Plasma membrane integrity of cryopreserved human sperm: an investigation of the results of the hypoosmotic swelling test, the water test, and eosin-Y staining

Objective: [1] To examine the relationship between sperm membrane integrity and motion parameters before and after cryopreservation; [2] to determine the capacity of the membrane integrity tests to predict the outcome of cryopreservation in fertile and infertile men; and [3] to examine the degree of agreement between tail and head membrane integrity of testicular and ejaculated immotile sperm cryopreserved for intracytoplasmic sperm injection. Design: Prospective study. Setting: Academic tertiary care institution. Patient(s): Fertile donors and normozoospermic oligozoospermic, and asthenozoospermic subfertile men. Intervention(s): Semen samples were cryopreserved and thawed for analysis. Main Outcome Measure(s): Sperm membrane integrity and computer-assisted motion parameters. Result(s): The hypoosmotic swelling test and water test had a significant and positive correlation in the fresh and cryopreserved ejaculates of all groups. The results of the hypoosmotic swelling test correlated positively with the percent motility in the Fresh ejaculates of fertile and subfertile men. None of the membrane integrity tests correlated with the cryosurvival rate in any group. In the ejaculated and testicular samples with no postcryopreservation motility, the simultaneous assessment of hypoosmotic swelling test and eosin showed that of 33% sperm exhibiting coiling with the hypoosmotic swelling test,only 9% were eosin negative, whereas 24% were eosin positive. Conclusion(s): [1] The water test may be a simpler replacement for the hypoosmotic swelling test; [2] none of the membrane integrity tests predicted sperm motility after cryopreservation; and [3] there was a high degree of disagreement between the hypoosmotic swelling test and eosin in the samples with no postcryopreservation motility. (Fertil Steril(R) 1998;70:1148-55. (C) 1998 by American Society for Reproductive Medicine.).